Image courtesy of http://endangered.fws.gov/i/C1M.html
site lists the status of endangered species. http://endangered.fws.gov/i/c/sac1m.html
adapted from image found at
Species Information 1996. http://fwie.fw.vt.edu/www/esis/lists/e154006.htm.
Accessed on Feburary 17, 2003.
Cay National Wildlife Refuge. General Information. http://caribbean-ecoteam.fws.gov/green_cay_index.htm.
Accessed on March 3, 2003.
Fish and Wildlife Service. Division of Endangered Species. http://endangered.fws.gov/i/c/sac1m.html.
Accessed on Feburary 17, 2003.
States Geological Survey. Status and Trends of the Nations Biological
Resources; Caribbean Islands. http://biology.usgs.gov/s+t/SNT/noframe/cr133.htm
Accessed on March 20, 2003.
Croix Ground Lizard
An adult St. Croix Ground Lizard averages 50-65 mm in snout vent length.
It is characterized by a dorsal pattern of light brown and dark brown
or black, white and dark brown logitudnal stripes, a light gray abdomen
with lateral blue margins, pinkish undersides of legs, throat, and chest,
and a tail pattern of alternating white and blue rings. (Endangered
1996, U.S. Fish and Wildlife) The pupil of the eye has a figure-eight
shape, and the iris a light grayish-brown. There are approximatly 2500
individuals located on Green Cay and 50 individuals on Protestant Cay.
(U.S. Fish and Wildlife) The St. Croix Ground Lizard inhabits leaf litter,
tidal litter, other loose substrate, and crab burrows in beachland and
upland forest. (U.S. Fish and Wildlife) The individuals feed on
small white moths, hermit crabs, sand flease, arthropods and crustaceans,
orchestria, annelids and dermaterones (U.S. Fish and Wildlife).
Little is known about the St.Groix Ground Lizard regarding development,
reproduction, or lifespan.
St. Croix Lizard was designated as endangered by the Endangered Federal
Register, June 3, 1977 (Endangered, 1996).
United States Federal Wildlife Service is responsible for the management,
recovery, listing and law enforcement/protection of this species (US
Fish and Wildlife).
Fish and Wildlife Service and National Park Service signed a cooperative
agreement in January 1982 for the National Park Service to provide protection
of the species on Green Cay National Wildlife Refuge (US
Fish and Wildlife).
only known remaining natural populations of the St. Croix ground lizard
(Ameiva Polops) are found within the US Virgin Islands off
the northern shore of St. Croix Island on Green Cay and Protestant
Cay (Endangered, 1996). These locations have both been designated
as critical habitat for A. polops.
introduction of the Small Indian Mongoose (Herpestes auropunctatus)
in 1984 and human disturbance are both responsible for the elimination
of A. polops from the mainland of St. Croix and continue
threaten the species viability. The Indian Mongoose is known to be
highly destructive to native reptile fauna when they become established
on small Islands or Cays (USGS). The accidental introduction of the
mongoose onto Green Cay or Protestant Cay would most likely result
in the extinction of A. polops.
Image courtesy of http://hbs.bishopmuseumhttp://hbs.bishopmuseum.org/good-bad/mongoose.html.org/good-bad/mongoose.html
The extensive development of coastal areas around St.
Croix also contributed to the decline in the population of A.
polops. “Beautification practices” like raking and
undergrowth removal modify critical features of
polops‘s habitat (Green Cay). These practices result in
a decline in leaf and tidal litter, loose substrate, and crab burrows
population of A. polops is currently estimated to be between
360-2500 on Green Cay and 50 on protestant Cay (Endangered, 1996).
Their small population
sizes and reduced habitat area make A. polops particularly
vulnerable to extinction as a result of genetic bottlenecking. If
a natural disaster of considerable proportions were to occur then
the entire species could be eliminated because there wouldn't be enough
genetic variability within the population for natural selection to
steps have been taken to help preserve the A. polops. The
most significant of these was the establishment of the Green Cay National
Wildlife Refuge in 1977 by the U.S. Fish and Wildlife service. This
was done to protect the largest remaining population of A. polops
(Endangered, 1996). The refuge provides protection for 14 of
the 18 acres of designated critical habitat for A. polops on Green
Cay and is closed to the public (Green Cay). However, if the species
is going to persist then more conservation measures need to be taken.
The current conservation goal for A. polops as stated by
National Park Service is to establish a stable population on Green
Cay and Protestant Cay and to establish a minimum self sustaining
population of 500 individuals on Buck Island Reef National Monument,
where no lizards are known to reside currently (Endangered, 1996).
This Island could serve as an experimental release sight for the lizards.
In order for this project to succeed a massive eradication program
must first be implemented to remove the Indian Mongoose from this
Recovery Plan approved by the U.S. fish and Wild life service in 1984
included the following suggestions:
The eradication of the Indian Mongoose in and around St. Croix.
This would allow the lizard to be successfully transferred and established
in areas such as Buck Island, where populations of lizards once
A few lizards should be transplanted to Zoos where they can be actively
bred for reintroduction later.
Human disturbance and housing and resort development should be restricted
in the area of the lizard’s habitat.
The continued protection of the habitat and present population on
implementation of these policies has potentially important economic
consequences. The full protection of Green Cay and Protestant Cay
would mean limiting potentially lucrative tourism in these areas.
Protestant Cay is currently leased by a hotel complex. In addition,
the eradication of the Indian Mongoose would require a considerable
degree of money, time and labor.
prospects for A. Polops do not look promising. Present
and future threats to the species are numerous and the measures needed
to insure their survival are costly. The future
of the A. polops populations will depend largely on the fate
of its remaining habitat. An
increase in human disturbance or habitat alteration resulting from
recreational activities, would be
detrimental. Given that A.
polops is a species of no commercial value and of little aesthetic
value when it comes to tourism, the incentive for taking the neccesary
steps to save this species do not appear strong at this time.
Robin Forbes-Lorman, Josie Caton, Sarah Biber
Creation/revision date: 4 April